There are a variety of prior art vaporizing devices known in the prior art, and a number of these devices are employed to direct vapors, in the form of steam, to a user's face.
U.S. Pat. No. 4,700,050, issued to Hennuy et al., discloses a boiler arrangement for use in a variety of electrical appliances, including a facial sauna and an inhaler. In this device a positive temperature coefficient thermistor is employed as the heating element, and this heating element is retained within a recess formed in the bottom wall of a liquid retaining cup. In the Hennuy device the recess divides the cup into two separate compartments, and does not permit the flow of liquid between these compartments. In addition, the boiler and heater arrangement described in the paragraph beginning on line 58 of column 2 will create a vigorous boiling of the water, making it difficult to control the volume and velocity of steam flow to the user's face.
U.S. Pat. No. 3,351,737, issued to Katzman et al., discloses a facial treatment device employing a hood with cooling air-inlet slots provided at the base thereof to prevent the build-up of a vacuum within the hood, and also to partially cool the steam. This device does not employ a system for positively controlling the volume or velocity of steam flow to the user's face. Moreover, the provision of air-inlet slots in the hood, as disclosed in Katzman et al., will not effectively cool the steam directed to a user's face; particularly when the user's face is sealed against the upper margin of the hood.
U.S. Pat. No. 3,152,240, issued to Scott, discloses a vaporizing device which is intended to be employed for health and complexion care. However, this device, like the devices described in the above-identified patents to Hennuy et al. and Katzman et al., does not employ a system for positively controlling both the volume and velocity of steam flow to the user's face.
Bernard Frank, the inventor of the subject matter described and claimed herein, and Melvin B. Greenberg have jointly invented facial treatment devices, in the form of facial saunas, which are the subject of U.S. Pat. No. 4,621,641. Improvements to the facial sauna devices described in the Frank et al. '641 patent are the subject of pending patent application Ser. No. 053,285, filed on May 22, 1987, and entitled Vaporizer and/or Facial Treatment Device. In the devices described in the latter patent and pending application steam is generated in a casing member and then directed through a collapsible hood arrangement for providing facial treatment to a user's face. These latter devices, like the devices described earlier herein, do not include any system for positively controlling the volume, velocity and temperature of steam flow to a user's face. However, these devices have worked satisfactorily for their intended purpose; particularly because the user's face is not intended to be positioned in sealing engagement with the flowdirecting collapsible hood thereof.
In addition to the disclosure in the above-discussed Hennuy et al. '050 patent, the use of PTC electrical heating elements are disclosed in Steiner et al. U.S. Pat. No. 4,324,974, and in Kleinschmidt et al. U.S. Pat. No. 4,223,208. Other systems wherein a heating element is included in a recess of a device are disclosed in Mayall U.S. Pat. No. 1,381,322; Bernard U.S. Pat. No. 1,308,836; French No. 88,3862 and British Patent Specification No. 166,416. None of the devices disclosed in the patents identified in this paragraph include an arrangement for effectively controlling the volume and velocity of steam flow in an apparatus, such an inhaler, which is designed to direct the steam to a user's face.